The present invention relates to user tokens, in particular contactless user tokens, and to reader devices that may be used to read such tokens. Certain embodiments of the invention relate in particular to contactless cards and to reader devices that may be associated with terminals such as automated teller machines (ATMs) or point of sale terminals.
Contactless cards or other tokens such as mobile phones are becoming more common, with more companies producing such contactless cards or other tokens and associated readers. By a contactless card or other token is meant a card or other token from which data may be read by a reader device without requiring physical contact between the contactless card and the reader device.
Known contactless cards are based upon radio frequency identification (rfid) technology, and include an r.f. transmit/receive antenna and a memory used to store financial, account, transactional, user or other data. The memory may be incorporated in a chip or integrated circuit together with a processor.
Such known contactless cards or tokens are classified as either passive or active. Passive cards do not contain their own power source. Instead, an electromagnetic signal received from a reader device is used to power operation of the card. The electromagnetic signal is received by the antenna on the card and is used to charge up a storage capacitor on the card. Active devices include their own power source, for instance a battery.
In operation, a reader device transmits a request for data to the contactless card in the form of an r.f. electromagnetic signal. The processor decodes the received signal and responds to the request by transmitting data stored on the card to the reader using the transmit/receive antenna. Typically, the data is then used in a transaction. In use, a contactless card is often placed in suitable proximity to the reader, for instance by tapping the card, or a wallet or other container containing the card, on pad that is placed a suitable distance from the reader, in order to enable it to be read, depending on the transmission power. If the transmission power is sufficiently high then the card may be read from on a user's person without requiring them to extract the card and place it near the reader.
Contactless cards or tokens may be used for instance as cash or credit cards, transport cards or season tickets, electronic wallets, security passes, driving licenses, or passports. A contactless card may be used as a SIM card in a mobile phone. In that case the card may communicate with a reader device either via r.f. communication circuitry embedded in the card or in the phone, or via the mobile phone network.
Reader devices may be found in, for instance, self service terminals such as automated teller machines (ATMs), merchant terminals or cash registers in shops or other point of sale terminals, security gates, transport ticket barriers or in hand-held units.
Contactless cards appear to offer both competitive and usability benefits, particularly when implemented on self-service terminals such as ATMs, or on point of sale terminals. The user does not have to insert a card or other token into a machine. Instead the card or other token may be read whilst it is on the user's person, for instance in a pocket or wallet.
Security for contactless card transactions is typically provided by encryption of data transmitted between the card and the reader, and by encryption of data stored on the card. Further security may be provided by ensuring that authorized reader devices have a limited transmission range, so that a user has to intentionally bring a card within range for it to be read.
However, there are some potential security problems with contactless cards. In particular, cards can be read against the user's wishes and without the user being aware that the reading of the card is taking place.
The card may be read from within a user's wallet or pocket, for example, without any indication of the card having been read. An unauthorized user could, for instance, implement a contactless card reader having a large transmission range, conceal it in an area that lots of people pass by, and read the card details of all of those passers by. The encrypted data that was obtained could then be subject to decryption techniques. The chances of obtaining at least some decrypted user data would be relatively high, particularly if large quantities of user data were obtained.
Another potential security problem is that unscrupulous merchants could read a card and debit a user account more than once for any given transaction, either by processing a single transaction multiple times using an authorized, visible reader device, or by using a second, hidden reader device. The user would not be aware that additional, unauthorized transactions had taken place.